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HEREDITY   AS    IT  RELATES    TO 
FEEBLE  MINDEDNESS. 

By 

C.  B.   McNaity,  M.  D., 
Kinston,  N.  C. 


Reprint   from 

THE  CHARLOTTE  MEDICAL  JOURNAL 

October,     1915. 


CHARLOTTE,  N,  C, 


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Digitized  by  the  Internet  Archive 
in  2013 


http://archive.org/details/heredityasitrelaOOmcna 


HEREDITY    AS    IT    RELATES    TO 
FEEBLE-MINDEDNESS.* 

By  C.  B.  McNairy,  M.  D.,  Kinston,  N.  C. 

In  discussing  this  subject,  I  trust  I  will 
not  be  expected  to  rely  upon  my  own 
observation,  experience  or  knowledge, 
which  is  quite  limited,  therefore,  I  will 
of  a  necessity,  be  compelled  to  quote 
freely,  from  psychologists,  biologists  and 
the  later  authors  on  wrorks  of  heredity 
and  feeble-mindedness,  giving  a  short 
summary  of  their  conclusions. 

Webster  defines  heredity  as  that  which 
descends  by  inheritance.  I  think  our 
former  ideas  of  heredity  have  been  very 
charitable  to  our  forebears,  in  that  we 
were  wont  to  trace  only  our  good 
qualities  of  manners,  intellect  and  social 
and  political  achievements  to  the  long 
ancestral  stream  of  blue  blood  or  royalty 
that  courses  through  our  veins,  and  our 
misfortunes,  mental  and  physical  afflic- 
tions to  something  entirely  foreign,  for 
instance,  to  evil  spirits,  witchcraftery,  the 
lack  of  social,  educational  and  religious 
environments. 

How  often  have  we  heard  it  said  that 
he  or  she  came  of  the  noblest  blood  but 
seems  possessed  of  the  devil,  not  for  an 
instant  dreaming  that  they  have  in- 
herited long  accumulation  of  ancestral 
weaknesses,  and  really  are  only  the  un- 

*Read  before  the  North  Carolina  Medical 
Association  in  Greensboro,  N.  C,  June  17,  1915. 


fortunate  objects  of  the  penalty  of  the 
sins  of  the  fathers. 

Mendel's  law,  which  he  discovered  by 
the  crossing  of  individual  plants,  mostly 
peas,  with  one  pair  of  contrasting  char- 
acters. His  method  consisted  in  cross- 
ing two  forms  having  distinct  characters 
and  counting  the  number  of  offspring  in 
successive  generations  showing  one  of 
the  other  of  these  characters. 

He  called  the  peculiarity  with  which 
the  two  plants  differed,  the  unit  char- 
acter, for  example,  the  tallness  or  the 
color  of  the  seed,  he  called  the  characters 
which  appeared  in  the  first  generation 
of  the  result  of  his  cross,  fertilization,  the 
DOMINANT.  The  one  that  did  not  ap- 
pear until  the  second  generation  he  called 
RECESSIVE  on  the  ground  that  it  was 
there  in  the  first  generation,  but  it  did 
not  appear  in  the  next  generation. 

Considering  the  spermatozoon  and 
ovum  in  animals.  It  was  found  that  if 
these  "germs  cells"  previous  to  being 
placed  under  the  microscope,  were  put  in 
some  kind  of  stain,  certain  bodies  ap- 
peared in  the  cells  because  they  had  ab- 
sorbed some  of  the  stain  or  coloring 
matter.  Nothing  was  known  of  the 
function  or  the  purpose  of  these  bodies, 
but  because  they  become  colored  under 
this  treatment  they  were  called  color 
bodies  or  chromosomes. 

"It  was  found  later  that  there  was 
practically  always  the  same  number  of 
these  bodies  in  the  germ  cells  of  the  same 
species  'of  plant  or  animal.     They  were 


thus  not  accidentally  colored  bodies,  but 
bodies  of  some  significance.  Futher- 
more,  it  was  discovered  that  there  is  a 
process  of  maturing  or  ripening  in  these 
cells  before  they  are  ready  to  unite  with 
the  cell  of  the  opposite  sex  for  the  forma- 
tion of  new  individual.  In  this  ripening, 
the  number  of  these  bodies,  or  chromo- 
somes, is  reduced  one-half." — (Feeble- 
Mindedness,  Goddard,  p.  534). 

"It  is  thus  seen  that  the  new  individual 
formed  by  this  union  of  these  two  mature 
cells  there  will  be  the  regular  number  of 
bodies,  or  chromosomes,  half  of  which 
have  come  from  each  parent.  It  was 
soon  concluded  that  these  chromosomes 
were  to  be  considered  the  bearers  of 
Heredity,  which  in  part  at  least,  explains 
the  mechanism  of  the  transmission  of  the 
traits  from  parents  to  children.  The  off- 
spring may  inherit  the  same  trait  from 
both  parents,  or  he  may  inherit  from 
only  one,  therefore,  we  have  duplex, 
simplex,  nulliplex,  giving  us  the 
Neomendelian  classfication  of  individual 
inherited  determiners.  For  reasons 
which  we  cannot  explain  here,  the 
biologists  conceive  that  each  chromosome 
has  within  it  what  are  called  determiners, 
that  is  certain  particles,  molecules  or 
elements,  which  contain  within  them- 
selves the  potential  organ  which  they 
represent,  or  some  quality  or  character- 
istic of  the  organ  such  as  the  color  of  the 
eye  or  of  the  hair.  If  the  individual  has 
brown  eyes  it  is  because  his  chromosomes 
carried  determiners  for  brown-  eyes.     If 


he  has  long  arms,  it  is  because  his 
chromosomes,  some  of  them  at  least, 
carried  determiners  for  long  arm  bones." 
—  (Feeble-Mindedness,  Goddard,  p.  536). 

"Many  investigators  have  carried  out 
similar  experiments  on  many  species  of 
animals  and  plants  and  have  greatly  ex- 
tended our  knowledge  of  the  principles 
of  inheritance  discovered  by  Mendel. 
But  in  the  main,  Mendel's  conclusions 
have  been  confirmed  again  and  again,  so 
that  there  is  no  doubt  they  constitute  an 
important  rule  of  inheritance  among  all 
organisms." — (Heredity  and  Environ- 
ment, Conklin,  pp.  250,  297). 

Breeders  have  long  known  that  it  is 
possible  to  get  certain  desirable  char- 
acters of  an  organism  from  one  race,  and 
other  desirable  characters  from  another 
race.  Since  the  discovery  of  the 
Mendelian  theory  of  Heredity,  such  new 
combination  of  old  characters  have  re- 
peatedly been  made,  and  with  almost  the 
same  certainty  of  results  as  when  the 
chemists  make  combinations  of  elements 
or  radicals.  This  is  the  chief  method  em- 
ployed by  Burbank  in  producing  his 
really  wonderful  new  creations  in  plant 
life.  By  extensive  hybridization,  he 
brings  about  many  new  combinations  of 
old  characters,  a  few  of  which  may  be 
commercially  valuable." — (Heredity  and 
Environment,  Conklin,  p.  379). 

"East  and  Shull  have  shown  that 
Hybrids  between  two  races  of  corn  may 
be  very  much  larger  and  more  fertile 
than  either  parent.     Unfortunately,  such 


hybrid  races  of  corn  do  not  breed  true 
and  crosses,  must  be  made  anew  in  each 
generation  if  maximum  results  are  to  be 
had.  Nevertheless,  this  method  of 
hybridization,  or  heterozygrosis,  as  it  has 
been  called,  offers  extremely  important 
means  of  quickly  producing  very  vigorous 
and  fruitful  individuals,  but  not  lines  or 
races  which  breed  true." 

"This  is  what  is  meant  by  the  control 
of  heredity ;  namely,  the  possibility  of 
preventing  the  reproduction  of  individ- 
uals with  bad  traits,  and  of  making  new 
and  favorable  combinations  of  old  traits 
by  means  of  selective  breeding,  and  of 
seizing  upon  and  perpetuating  new  and 
favorable  mutations." 

"The  Mendelian  association  and  dis- 
association  of  characters  produce  new 
forms  of  adult  and  plants,  but  not  new 
Heredity  Characters.  New  combination 
of  factors  may  be  compared  to  new  com- 
binations of  chemical  elements.  You  can 
always  get  out  of  the  combination  what 
went  into  it.  The  actual  origin  of  new 
hereditary  characters  or  mutations  is  ob- 
scure. Many  individual  modifications 
may  be  produced,  which  do  not  become 
racial.  In  most  cases,  such  mutations 
consist  in  the  dropping  out  of  some  old 
character  rather  than  in  the  addition  of 
a  new  one." 

"Science  has  taught  us  something  of 
the  wonderful  stability  of  the  past  time 
and  of  future  ages — something  of  the 
eternity  of  natural  processes — it  is  surely 
not    possible,    to    improve    on    nature's 


method  of  eliminating  the  most  unde- 
sirable lines  from  reproduction.  This  has 
been  the  chief  factor  in  the  establish- 
ment of  the  races,  of  domesticated 
animals  and  cultivated  plants.  The  im- 
provements of  environment  and  oppor- 
tunities for  individual  development,  en- 
ables men  at  the  present  day  to  get  more 
and  more  of  their  heredity  than  was  pos- 
sible in  the  past.  The  advance  of  civiliza- 
tion has  made  only  improvements  of  en- 
vironment, but  neither  environment  nor 
training  change  the  hereditary  capacity 
of  man.  There  has  been  no  perceptible 
improvement  in  human  heredity  within 
historic  time.  Nothing  comparable  with 
the  changes  which  have  occurred  in 
domesticated  animals.  Indeed,  no 
modern  race  of  men  is  the  equal  of  certain 
ancient  ones.  The  method  of  elimination 
by  the  destruction  of  the  weak,  cowardly, 
and  antisocial  which  was  the  method 
practiced  in  ancient  Sparta  is  repungent. 
The  worst  forms  of  mankind  may  be  pre- 
vented from  propagating,  and  the  best 
t3Tpes  may  be  encouraged  to  increase  and 
multiply. 

"Children's  children  are  the  crown  of 
old  men  and  the  glory  of  children  are 
their  fathers."     Prov.  17:6. 

"Galton  has  pointed  out  the  fact  that 
in  the  little  country  of  Attica  in  the 
century  between  530  and  430  B.  C.  four- 
teen illustrious  men,  one  for  every  four 
thousand  three  hundred  of  the  free  born 
adult  male  population." 

In  the  two  centuries,   500  and   300   B. 


C,  this  small  barren  country,  with  area 
and  total  population  about  equal  to  that 
of  the  present  state  of  Rhode  Island,  with 
less  than  one-fifth  of  the  free  population, 
produced  twenty-five  of  the  illustrious 
men.  Among  whom  were  Pericles, 
Aristodes,  Comon,  Themistocles,  Euri- 
pides, Sophocles,  Socrates,  Plato,  Aris- 
totle,. Demosthenes  and  others.  These 
illustrious  men  came  from  a  remarkable 
race,  composed  of  individuals,  by  a  pro- 
cess of  unconscious,  but  severe  selections. 
Athens  was  the  intellectual  and  social 
capital  of  the  world  and  to  it  the  most 
ambitious  and  capable  men  were  irresist- 
ably  drawn.  It  was  a  good  heredity  as 
well  as  good  imigration  that  made 
Athens  famous." 

"Galton  concludes  that  the  average 
ability  of  the  Athenian  race  of  that  period 
was,  on  the  lowest  possible  estimate,  as 
much  greater  than  that  of  the  English 
race  of  the  present  day,  as  the  latter  is 
above  that  of  the  African  Negro." 

"Social  morality  grew  exceedingly 
fast,  marriage  became  unfashionable  and 
was  avoided.  Many  of  the  more  ambi- 
tious and  accomplished  women  were 
avowed  courtesans,  and  consequently  in- 
fertile, and  the  mothers  of  the  incoming 
population  were  of  the  heterogeneous 
class.  It  is  therefore  no  surprise  to  us 
that  the  high  Athenian  breed  decayed 
and  disappeared."  "He  that  begetteth 
a  fool,  doeth  it  to  his  sorrow,  and  the 
father  of  a  fool  hath  no  joy.  A  foolish 
son  is  a  grief  to  his  father,  and  bitterness 


to  her  that  bare  him."     Prov.  17:21  and 

25. 

The  best  authorities  of  today  give 
heredity  as  the  direct  cause  of  feeble- 
mindedness in  75  per  cent,  of  the  cases 
with  the  most  conservative,  others 
holding-  that  as  much  as  90  to  95  per  cent, 
of  all  feeble-mindedness  is  due  to  hered- 
ity."—(Dr.  H.  H.  Goddard,  Vineland,  N. 
J. ;  Dr.  Burnstine,  Rome,  N.  Y. ;  Dr.  Rich- 
ard Cabot,  Boston,  Mass. ;  Dr.  Fernald, 
Waverley,  Mass.). 

"Feeble-Mindedness  produces  more 
pauperism,  degeneracy  and  crime  than 
any  other  one  force.  It  touches  every 
form  of  charitable  activity.  It  is  felt  in 
every  part  of  our  land.  It  effects  in  some 
way  all  our  people.  Its  cost  is  beyond 
our  comprehension.  It  is  the  unappre- 
ciated burden  of  the  unfortunate.  It  is 
a  burden  we  are  compelled  to  bear; 
therefore,  let  us  bear  it  intelligently,  to 
the  end  that  the  chain  of  evil  may  be 
lessened,  the  weak  cared  for  and  the 
future  brighter  with  hope  because  of  our 
effort. 

"Ye  who  are  strong  must  bear  the  in- 
firmities of  the  weak." — (Amos  W.  But- 
ler). 

"There  can  be  no  doubt  that  the  main 
characteristics  of  every  living  thing  are 
unalterably  fixed  by  heredity.  Men 
differ  from  horses  or  turnips  because  of 
their  inheritance.  Our  family  traits 
were  determined  by  the  hereditary  con- 
stitutions of  our  ancestors,  our  inherited 
personal  traits  by  the  hereditary  consti- 


tutions  of  our  fathers  and  mothers.  By 
the  shuffle  and  deal  of  the  hereditary- 
factors  in  the  formation  of  the  germ  cells 
and  by  the  chance  union  of  two  of  these 
cells  in  fertilization,  our  hereditary 
natures  were  forever  sealed.  Our  ana- 
tomical, physiological,  psychological  pos- 
sibilities were  predetermined  in  the  germ 
cells  from  which  we  came.  All  the  main 
characteristics  of  our  personalities  were 
born  with  us  and  cannot  be  changed  ex- 
cept within  relatively  narrow  limits. 
'The  leopard  cannot  change  his  spots  nor 
the  Ethiopian  his  skin,'  and  'though  thou 
shouldest  bray  a  fool  in  a  mortar  with 
a  pestle  yet  will  not  his  foolishness  de- 
part from  him.'  Race,  sex,  mental 
capacity  are  determined  in  the  germ  cells, 
perhaps  in  the  chromosomes,  and  all  the 
possibilities  of  our  lives  were  there  fixed, 
for  who  by  taking  thought  can  add  one 
chromosome,  or  even  one  determiner  to 
his  organization?" 

(Conklin,    Heredity    and    Environment, 
Page  447.) 

It  has  been  well  said    that    there    are 
three  important  events  in  a  man's   life : 
"His  ingress  into  the  world. 
His  progress  through  the  world. 
His  egress  out  of  the  world. 
His  ingress  into  the  world  is  naked  and 

bare. 
His  progress  through  the  world  is  trouble 

and  care 
His  egress  out    of    the    world    is,    God 

knows  where 


10 


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well 


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